A device includes a field effect transistor on an insulating film. A first fin extends vertically from a top side of a horizontal surface of a semiconductor substrate. An epitaxial cap rests on the first fin, with a left vertex on a left side of the epitaxial cap at a first horizontal distance from a reference line that vertically bisects the first fin, and a right vertex on the right side of the epitaxial cap at a second horizontal distance from the reference line, the first horizontal distance being at least twenty percent greater than the second horizontal distance; and a top vertex is at a third horizontal distance to the left of the reference line.